Workholder



Feb. 5, 1963 M. FRIEDLAND ETAL 3,076,644

WORKHOLDER '7 Sheets-Sheet 1 Filedug. .12 1959 Feb. 5, 1963 M. FRIEDLANDET AL 3,076,644

WORKHOLDER 7 Sheets-Sheet 2 Filed Aug. 12, l1959 QN WK Feb. 5, 1963 M.FRIEDLAND ETAL 3,076,644

/WORKHOLDER Filed Aug. 12, 1959 7 Sheets-Sheet 5 fifa' TORNEYS Feb- 51963 M. FRll-:DLAND ErAL 3,075,544

WORKHOLDER WORKHOLDER Feb- 5, 1963 M. FRIEDLAND v1:1- AL 3,076,644

ATTORNEYS Feb. 5, 1963 M. FBIEDLAND ETAL WORKHOLDER '7 Sheets-Sheet 7Filed Aug. 12, 1959 Martin Friedland,

United States Patent-Utilice mld Patented Feb. 5, 1963 Philadelphia, andFrederick W. Schneider, Levittown, Pa., assignnrs to Wiedemann MachineCompany, King of Prussia, Pa., a corporation of Pennsylvania p FiledAng. I2, 1959, Ser.No. 833,315 21 Claims. V(Cl. 269-452) The presentinvention relates to workholders for inachine tools.

Av purpose of the inventionis to advance a workholder by a thruster andto close the jaws of the workholder by forward motion of the thruster.

A further purpose is tolock the jaws Yagainst vclosing until the'workholder carriage has fully advanced.

i at the same time lock the carriage and permit the cam collar to moveforward and close the workholder jaws, re-

versing the operation on retraction.

A further purpose is to automatically releases and retract one ofseveral worlcholders holding a worl; piece when danger of interferencearises.

Further purposes appear inthe specification and in the claims.

In the drawings we have chosen to illustrate only one of the numerousembodiments in which the invention appears,` selecting the forms shownfrom the standpoints of convenience in illustration, satisfactoryoperation and clear demonstration of the'principles involved.

FIGURE l is a top plan view of one of the worlrholders of the presentinvention.

FIGURE 2 is a `fragmentary side elevation of the Workholder of FIGURE l.

FIGURE 3 is a fragmentary enlarged section on the line 3-3 of "FIGURE 1.

FIGURE 4 is an enlarged front end elevation of the workholder of theinvention taken on the line 4-4 of FIGURE 2.

FIGURE 5 is an enlarged section on the line 5--5 of FIGURE 2.

FIGURE 6 is a diagrammatic fragmentary top plan view of a machine toolaccording to the invention, showing two of several` workholders.

FIGURE 7 is an end elevation of FlGURE y6 taken on the line 7 7.

FIGURE 8 is a central vertical section of the workholder of theinvention, the section being taken on the line S-S of FIGURE 5 toreduced scale. j

FIGURES 9 to ll are views showing other positions of the `workholder of4FIGURE 8.

FIGURE 12 is an electric circuit diagram of the device oi the invention.

voperation of machine tools, especially turret Ipunch press gaugingtables, there is an increasing need for work- Y holders which canoperate to engage and release andad vance and retract work by remotecontrol.

Furthermore in such devices where there Aare a plurality of workholders,it may be necessary tocarry the work to a position in which anindividual worlcholder vwould interfere with the machine tool or bedamaged.

- 7construction `and` convenicnt'in voperation,,performing its mainfunctions entirely under the` control lof a thruster and .of .auxiliarylocking devices.

A sliding guide Ztl, suitably of box formation,` is supportedon shimpads 21 restingvon a laterally movable carriage 23. `Socket head Vcapscrews 22-fextend through the carriagel and are threaded into tappedholes 22 in the sliding guide`2ll to secure thev slidingguide 20 tothelaterallyniovable carriage 23. The slidinggnide 2n l is Vlevelledonthe carriage 23 byzshims 23..

A` -dowel 222 passes through holes 23' and 224 and positionsthe-slidingA guide `Zilrelative to the laterally movable carriage 23.

The carriage 23 has guide surfaces 25 which slide "transversely of themach-ine tool on ways 2d which explaced `a forwardly and-backwardly-rnoving'carriage 32,

Yit

generally of'channel formation and capableof telescoping inside thesliding `guide andinioving -forward beyond `The carriage 32st theforward end has iixed thereon lowerl and upper bearing lugs 33 and 34,and on the bearing lugs are pivoted lower workholder jaw 35 and upperworkholder jaw 35 on pins 3? and 318 extending through openings in thelugs and the jaws.

Threaded studs 39 and nuts 39 swivelly connect toggle r pads'i) to the'jaws at dll.

`carries roller ypins 43 journalling cam rollers 432 which A rideon camsurfaces 433011 the top of sides 44. Pins-434 carry cam rollers 435which ride on cam surface 436 vwhich isk onthe bottom of 'sides-44.`iii/ear strips, not

shown, Vextending in the direction of motion of the carriage,- aresuitably securedv to Ythe sidesJ of the cam `collar 43 and bear againstspaced sides 44 at 437. The ycam collar 43 is limited to-:sideward`motion by 'thesides 144 Y and is limited in forward motion by the strokeof the hydraulic cylinder 5l.

A tieplate 45 extends vacross-the fro-nt of the carriage and is suitablysecured to'sidesdl behind the gripping lportions of the rjawspthussupporting the sides 4d together. Within thisrange .the cam collar ispermitted to rnove forward and its lower' cam rollers 46 journalledonpins 46 engage successively cam surf-aces 41 and 42 on the lowersurface of the lower jaw.- The upper jaw has rst and second cam surfacesi7 and llon the ,top surface which aresuccessively' engaged Vby, cam

rollers 50 journalled on pins 50' on the upper portion of the camcollar.

A locator 49 is secured to a retainer 49 by cap screws 492. The retainer49 is of generally rectangular form with a lever receiving notch 493 anda latch extension 494. Shoulder screws 495 pass through diagonalelongated slots 496 and slidably connect the retainer 49 to the sidepiece 44.

A helical spring housing 497 suitably secured to side piece 44 retainshelical spring 498 which urges plunger 499 which bears against retainer49' and biases the retainer downward.

Actuator 491 slidably mounted in actuator housing 4911 is urged rearwardby helical spring 4912 wound about dowel 4913 acting against springabutment 4914 on the housing and spring abutment 4915 on the actuatorbiases the actuator rearward.

Actuator extension 502 slidably supports retainer 49' at 494.

Lever `4916, having perpendicularly displaced arms 5t)3 and 504, ispivotally connected to side 44 by pin 565. Arm 503 engages slot 493 onretainer 49.

A thruster, suitably a double acting hydraulic cylinder 51, is mountedat 52 at the back of the sliding guide 20, and has a piston and rodcombination 53 which extends forward in the carriage. The thruster isoperated by a solenoid operated hydraulic control valve 54 carrying abuilt in control valve which supplies hydraulic uid selectively toopposite ends of the cylinder through pipes 55 and 56. The pump andvalve assembly is conveniently located on top of the sliding guide asbest seen in FIG- URES 1 and 2.

At the rear of the sliding guide the housing 57 is extended down andholds suitable control equipment, as later explained.

At the forward end, the piston rod of the thruster connects with alongitudinal cam 58 which at the forward end is secured to a cross piece66 in the cam collar. The cross piece 60 is located between the jaws 35and 36 and the cam 58 extends through an opening between the lugs 33 and34 located in the front of the carriage.

Cam 5S has a forward straight track 61 on both sides which correspondsto locking of the cam collar, an intermediate slope 62 on both sides anda rearward straight track 63 on both sides which corresponds tounlocking the cam collar. The cam 53 also has a stop abutment 64 at itsrearward end.

The cam 58 passes through an opening in and is surrounded by a camfollower 65 having suitable approach surfaces to permit it to ride theslope of 62 and otherwise follow one of the other cam surfaces 61 or 63.i The cam follower 65 is retained in position against movinglongitudinally with respect to the carriage by transverse guide pins 66shown in FIGURES 1, 3 and 14, and has a notch 67 at one side whichreceives one ball end 68 of a toggle lever 70 pivoted on pin 71intermediate its ends in the side wall of the carriage 32.

The rear end of the toggle lever 70 has a ball end 72 which engages in anotch 73 of a laterally movable locking pin '74.

The locking pin is guided by a tubular bearing 75 in the carriage andrides a track 76 in the sliding guide over a portion of the travel ofthe carriage. When the carriage reaches a forward position, locking pin74 engages in hole 77 in support guide 2t] (FIGURE 3).

When the carriage moves forward to its limiting position, adjustablestop 78 on the back of the carriage engages bumper St) on the slidingguide as shown in FIG- URE 9. A trip mechanism 81 extends along thecarriage 32 guided on guides 82 and extends into a slot S3 in thesliding collar. The trip mechanism d1 is fixed to and slides withcarriage 32. The end of trip mechanism S1 is beveled to engage roller101i of limit switch Miti. Roller G is spring biased by helical spring1662. Contact is made at 10G3 when trip mechanism 81 slides away fromroller 199', and contact is broken when trip mechanisrn 81 engagesroller 109 and forces it upward.

The cam collar 43 has pins 84 and 85 which engage the insides of thegripping jaws. When the collar is retracted the pin S5 holds the upperjaw up, and the pin S4 forces the lower jaw down.

In FIGURE 12, we show an electric circuit Suitable to operate the deviceof the invention and including power leads 36 and 87, the lattersuitably being grounded. The leads are desirably connected to a sourceof alternating current at 1l() volts, 60 cycles. An approach responsivedevice 38 is connected across between the leads and located at thebottom of the housing 57 where it can respond to approach to a dangerarea indicated by interference pattern (FIGURE '7) suitably placedbeneath the machine. The interference pattern 9i) may suitably bc ofmagnetically susceptible material (such as steel) which will causeresponse in the approach responsive device S8. If desired, however, thedevice SS may be a limit switch instead of an approach responsivedevice.

The relay in the approach responsive device 38 has one set of normallyclosed contacts SS-l and one set of normally open contacts 88-2.

The normally closed contacts 33-1 are in series with one set of contacts92 of switch 91 and one set of contacts 93 of switch 94 and with thesolenoid valve 95 which tends to throw the hydraulic valve into positionto advance the thruster 51 forward and clamp the work.

Thus in normal automatic operation, the solenoid is energized throughcontacts 92 of switch 91 and through contacts 93 of switch 94 and closedrelay contacts 88-1 to move the thruster to its extreme forward positionand clamp the work in the jaws.

Additional circuit units similar to those described can be connected at99.

If the equipment (gauging table) moves to a position where theworkholder is liable to be damaged by further operation of the machine,the approach responsive device S8 cornes into proximity with the pattern90 and the relay in the approach responsive device 3S picks up, openingnormally closed contacts Sii-1 and closing normally open contacts 88-2.Solenoid valve 95 is energized, throwing the hydraulic valve into theposition to retract the thruster 51, open the jaws and retract thecarriage. As long as the gauging table remains in the danger area, theapproach responsive device remains energized and the particularworkholder remains retracted, although other workholders not in thedanger area are supporting the work and retaining it in the properposition.

When the gauging table moves away from the danger area, the approachresponsive device is deenergized and the control relay returns to normalcondition.

The hydraulic valve then is shifted by solenoid 95 to advance theworkholder and grip the work.

Although one workholder may release and another take hold, this does notchange the position of the work as the Iwork is being held by otherworlrholders.

Thus it will be evident that when one of several workholders approachesa dangerous area, it will automatically release and then, if the dangerpersists sufficiently long will retract. As soon as the danger clears,the reverse operation takes place automatically. Thus, if the work movesfrom side to side of the machine through the turret punch press or thelike, the successive workholders will release and then take hold again,but the work will always be held properly by the remaining workholders.

In manual operation, any workholder can be retracted independently ofother workholders by operating switch 94 to open normally closedcontacts 93 and close normally open contacts 97. This deenergizessolenoid valve 95 which urges the workholder forward and energizessolenoid valve 95 which opens and retracts the workholder.

When all worlrholders are to be clamped and unclarnped in unison this iscontrolled by switch 9i. If switch 93. is shifted to open contacts 92and close contacts 98, the forward acting solenoid valve 95 will beaar/asas deener'gizesfthe retract-ing solenoid 9601i the workholder.When it is desired to'load the work in the workholder,

'switch l'9-1 is lmanually shifted to opencontacts- 92 and to closecontacts tlto energize the retracting solenoid 96 on each workholder.

The workholder ljaws 35and 36 are opened by theVV collar 43 which isfbeingmoved rearward bythe thrusterl. This continues "until the trip`mechanism S1 engagesl roller Idil on limit switchltltl.

Trip mechanisrni is adiustedso that the jaws are fully t unclamped `whenthe `switch loll is activated, an-d this vprevents Vthe lockingpiddfronrbeing withdrawn. Thus the workholders are inltheirffullyextended position when thework isbeingl clamped and unclampedfor-loading vand unloading respectively. e

Limit switch' 101i istused in coniunction with relay -102 tov indicatewhenl the workholde'r `is` retracted from the dangerV area.y When theworkholder reaches the-extreme retracted position limit switch lill isclosed and control relay 102 is energized. The relay ylin-remainsenergized aslong as'tliew'orkholdereis `in the retracted position actu-Relay '162 is thus capable of ating 'limit switch 161. providing anyrequired interlo'cks with the machine tool.

lelrwing ynow described the operation of the electricaldevice,`the^operation of the workholder mechanism is as follows:

`Considering first Vthe positionof FIGURE S, with the thruster fullyretracted, the follower 65 is engaging cam track6l, and the toggleleveris in the position in which pin 'M is retracted and is locked inthat position by engagement with track 76. The cam follower 65 is notper- Vmitted to ride upthe cam slope`62 because of the locking frommoving down by track 75 until the position of lFIGURE 9 is reached,Where Tpin 74 has'passed beyond the front of the track 76. Up to thistime the cam collar has `been locked against forward motion by thepin'l'd and toggle lever 7d which are acting oncam follower 65 to holdcam' 58 against moving forward in the carriage.

At this time, locator e9 is being held in a rearward or retractedposition relative to sides 44 at the forward end of carriage 32.

The locator assembly, during retraction in thefprevious cycle, was inthe position shown in FIGURE 13.A When the carriage was fully retracted,actuator 4910 at its rearward end contacted the sliding guide ldan'd waspushed forward relative to the carriage 32. This caused actuatorextension Sil? to slide along andV clear 'latch extension 494. Retainer49 was free to move downward and rearward along shoulder serein/S495under the biasing action of springe. During the advance phase, theretainer i9 is held from moving upwardly and forwardly 4relative to thecarriage by actuator extension 562 engaging latch In this position, thelocator is held retracted and is not in a position to bump the edge ofthe work sheet at the forward end of the advance phase of the cycle atthe clamp position. To advance the locator to the work sheets d Thus the`locator 49 was not in position to bump the `edge of the sheet when thejaws move forward and grip, but subsequently achieves the correctposition against the edge of the sheet and holds the sheet againstslipping laterally.

Now as shown in FlGURES 3 and 10, pin '74 moves to locking position andpositively locks the carriage in forl `ward position, while the lever 7ddellects the follower 65 upward as shown in FiGURE l0` and allows thecam'SS to move forward, the follower o5 engaging cam track 63. Camcollar d3 moves forward and lower cam rollers d( i raise the lower jawto .horizontal 'position by ridingalong cam surface 4l and then later asshown in FIGURE ll hold the lower jaw `horizontal by engaging cam.surface 42. #In -the meantime, as the cam collar moves forward betweenthe positions fof FIGURES 1.0` and ll, under the action of the thruster,the upper cam rollers dll on the cam collar act on rhecam surface S onthe upper jaw and the upper toggle pad grips the work at ltlZ. Forwardmotion of cam collar d3 is limited by cam surface dd, and in turn thejaw positioniof jaws 3S and 36 is determined by the work piece beingclamped. lt is evident that all thicknesses of work material withinV thecapacity of the machine-may beclamped without any adjustment.

The cycle is completed by a reversal of the sequence of FIGURES 8 to l'las described above.

The locator i9 is suitably set before the jaws closeon the work, lso asto properly locate the work withrespect to the table in its correctposition.

yIt will be understood that this complete cycle will 'take place onlywhen the individual workholder is in danger oi" interfering with theoperation being done on the work piece. To load and unload 'the work inthe plurality of workholders, the carriagesl are kept in a 'forwardposition while the jaws 35 `and`36 are in lthe'openv position'f aspreviously explained.

In view oi our invention and disclosure, variations and modiications tomeet individual whim or particular need -will'doubtl'ess become evidentto others skilled in the art, to obtain all or part of thebenelits ofour invention without copying the structure shown, and we, therefore,claim all such insofar as they fall within the reasonable spirit andscope of our claims.

Having thus described our invention what we claim as new and desire tosecure by Letters Patent is:

l. ln a workholder, a sliding guide, a thruster mounted on the guide, aforwardly and backwardly moving carriage slidable on the sliding guide,pivoted jaw means on the forward end of thecarriage, and caml means onthe forward end of the carriage acting on the jaw means, said cam meansbeing interconnected with the thruster, thecarn means acting on thecarriage to move the carriage forward and then on the jaw means to closethe jaw means, and in retraction acting on lthe jaw means 'to open thejaw means and'thcn acting on the carriage to retract the carriage.

2. A workholder of claim 1, in combination with means acting on the cammeans during a portion of the stroke of the carriage to lock the-cammeans'with respect means 'for locking the cam means with respect to thecarriage during a predetermined portion of the travel of `the carriageand then unlocking the cam means, and means actuated by thethruster forlocking `the carriage in forward position. i

5. A workholder of claim l, in which the jaw means includes swingableelements, and jaw pads swivelling on the swingable elements.

6. ln a workholder, a guide, a carriage slidabie on the guide, athruster mounted on the guide, workholder jaw means mounted on theforward end of the carriage, and

emessa 7 adapted to open and close, cam means mounted on the forward endof the carriage and adapted to move with respect to the carriage andopen and close the jaw means, second cam means on the forward end of thethruster intereonnected to the first cam means and operative onlongitudinal motion of the first cam means, a follower engaging thesecond cam means, and means for locking the follower with respect to thesecond cam means and thereby preventing relative motion of the first cammeans with respect to the carriage during a portion of the forwardstroke.

7. A workholder of claim 6, in combination with means releasing thesecond cam means at a forward position of the carriage.

8. A workholder of claim 7, in combination with means operated by thesecond cam means for locking the carriage in forward position.

9. A workholder of claim 7, in combination with toggle means operated bythe second cam means for locl'- ing the workholder in forward position.

10. A workholder of claim 7, in combination with means operated by thesecond cam means for releasing the first cam means, to move forwardunder the action of the thruster with respect to the carriage and closethe jaw means.

ll. ln a workholder, a sliding guide, a thruster mounted on the guide, acarriage slidable on the sliding guide, pivoted jaw means on the forwardend of the carriage, cam means on the forward end of carriage acting onthe jaw eans, said cam means being -interconnected with the thruster,the cam means acting on the carriage to move the carriage forward andthen on the jaw means to close the jaws means, selectively operativemeans to open the jaw means while the carriage is extended forward, forthe purpose of loading, and means for preventing retraction of thecarriage during loading.

12. A plurality of workholders adapted to engage a single piece of workat the same time, support means common to said plurality of workholders,each of said workholders comprising a sliding guide, a thruster mountedon the guide, a forwardly and backwardly moving carriage slidable on thesliding guide, pivoted jaw means on the forward end of the carriage andcam means on the forward end of the carriage acting on the jaw means,first means for moving said thruster on each of said Workholdersforwardly and bacliwardly, and second means for moving a thruster of anindividual workholder of said plurality of workholders backwardly whensaid individual workholder encroaches on a predetermined space.

13. In a workholder, a sliding guide, a carriage slidable on the guide,jaw means pivotally mounted on the front of the carriage, a cam collarsurrounding the jaw means and adapted in one position to close the jawmeans and in another' position to open the jaw means, a thrusteroperating in the direction of motion of the carriage, interconnected tothe cam collar and adapted in forward position to move the cam collarwith respect to the carriage and close the jaw means, second cam meansinterposed between the cam collar and the thruster, and means acting onthe second jaw means for locking the cam collar with respect to thecarriage during a portion of the forward stroke.

14. A workholder of claim 13, in combination with a follower for thesecond cam means, a pin on the carriage, means interconnecting the pinand the follower, and a track on the guide engaging the pin and lockingthe second cam means against relative motion to lock the cam collar.

15. A workholder of claim 13, in combination with means for locking thecam collar with respect to the carriage during a portion of the foiwvardmotion and toggle means for locking the carriage with respect to thesliding guide in forward position and thereby releasing the cam collarfor forward motion to close the jaw means.

16. In a workholder, a carriage, pivoted jaw means on the forward end ofthe carriage, a work locator having a forward position and a retractedposition adjoining the line of meeting of the jaw means, and located onthe Side of the work between the jaw means and the carriage, means forretracting the work locator to a rearward position remote from the jawmeans, said means for retracting the work locator comprising springmeans urging the work locator toward retracted position and latch meansfor holding the work locator in retracted position, means for advancingthe work locator to a forward position adjoining the jaw means, andmeans operated by the position of the carriage for actuating the latchmeans to release the work locator from forward position and latch thework locator in retracted position.

17. A Workholder of claim 16, in combination with manually operablemeans for shifting the worlr locator from retracted position to forwardposition, and latch means holding the Work locator in forward position.

18. In a workholder, a sliding guide, a carriage slidably forwardly andin retraction on the guide, jaw means pivotally mounted on the front ofthe carriage, a cam collar surrounding the jaw means and adapted in itsone position to cam the jaw means closed and in another position to camthe jaw means open, a thruster operating longitudinally of the slidingguide interconnected with a cam collar and adapted to move the camcollar independently of the motion of the carriage when the carriage isin forward position so that the motion of the thruster on the cam collarcan close the jaw means.

19. A workholder of claim 18, in combination with locking means forlocking the cam collar with respect to the carriage during a portion ofthe forward stroke.

20. In a workholdcr, a carriage, opposed pivoted jaw means on theforward end of the carriage, the jaw means being adapted to engageopposite sides of work in sheet or plate form, a work locator having aforward position in which it engages the edge of the work when it isheld by the pivoted jaw means and having a retracted position remotefrom the work, the work locator being in line with the work when held.by the jaw means and located between the jaw means and the carriage,means for retracting the work locator to its rearward position remotefrom the jaw means and means for advancing the work locator to itsforward position in which it engages the edge of the work when the workis held by the jaw means.

21. A worlrholder of claim 20, in which the means for retracting thework locator comprises spring means urging the work locator towardretracted position, and latch means for holding the work locator in saidretracted position.

References Cited in the le of this patent

1. IN A WORKHOLDER, A SLIDING GUIDE, A THRUSTER MOUNTED ON THE GUIDE, AFORWARDLY AND BACKWARDLY MOVING CARRIAGE SLIDABLE ON THE SLIDING GUIDE,PIVOTED JAW MEANS ON THE FORWARD END OF THE CARRIAGE, AND CAM MEANS ONTHE FORWARD END OF THE CARRIAGE ACTING ON THE JAW MEANS, SAID CAM MEANSBEING INTERCONNECTED WITH THE THRUSTER, THE CAM MEANS ACTING ON THECARRIAGE TO MOVE THE CARRIAGE FORWARD AND THEN ON THE JAW MEANS TO CLOSETHE JAW MEANS, AND IN RETRACTION ACTING ON THE JAW MEANS TO OPEN THE JAWMEANS AND THEN ACTING ON THE CARRIAGE TO RETRACT THE CARRIAGE.